Details
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Bug
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Resolution: Incomplete
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Not Evaluated
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None
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5.14.2.2
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None
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This was being run on Windows 10.
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Windows
Description
This bug was found when trying to create a custom comboBox that has checkboxes. Below is the following code:
class CheckableComboBox(QtWidgets.QComboBox):
def _init_(self, parent: QtCore.QObject) -> None:
super()._init_(parent=parent)
self._checkedItems: List[bool] = []
self.view().pressed.connect(self.handleItemPressed)
self.setModel(QtGui.QStandardItemModel(self))
self.model().itemChanged.connect(self.onItemChanged)
@QtCore.Slot(QtGui.QStandardItem)
def onItemChanged(self, item: QtGui.QStandardItem) -> None:
if item.row() < len(self._checkedItems):
currentState = self._checkedItems[item.row()]
isChecked = item.checkState() == QtCore.Qt.Checked
if currentState != isChecked:
self._checkedItems[item.row()] = isChecked
@QtCore.Slot(QtCore.QModelIndex)
def handleItemPressed(self, item: QtCore.QModelIndex) -> None:
self.setCurrentIndex(item.row())
self.hidePopup()
def addItem(self, *args) -> None:
super().addItem(*args)
item = self.model().item(self.count() - 1, 0)
item.setFlags(QtCore.Qt.ItemIsUserCheckable | QtCore.Qt.ItemIsEnabled)
item.setCheckState(QtCore.Qt.Checked)
self._checkedItems.append(True)
def removeItem(self, index: int) -> None:
del self._checkedItems[index]
super().removeItem(index)
Upon removing and adding items to the custom combobox, you eventually run into an error message in event filters. There seems to be no root cause on the number of times, but usually within a minute (and certainly within 10minutes) of adding and removing items to the combobox. An error occurs that seems to suggest a possible issue in the memory allocation. The lines that cause the issue are highlighted in bold above and is to do with setting values on the QStandardItem. The error that is produced is below:
2021-02-18, 11:19:50 TypeError, 'PySide2.QtWidgets.QApplication.notify' called with wrong argument types: PySide2.QtWidgets.QApplication.notify(QMenu, QStandardItem) Supported signatures: PySide2.QtWidgets.QApplication.notify(PySide2.QtCore.QObject, PySide2.QtCore.QEvent)
{{}}
An interesting point to note, if in the event filter you simply change the class to QEvent, it carries on correctly and does not complain. Example code below:
class Application(QtWidgets.QApplication):
...
def notify(self, receiver, event):
if not isinstance(event, QtCore.QEvent):
logger.warning("Event has the wrong class type.")
event._class_ = QtCore.QEvent
return QtWidgets.QApplication.notify(self, receiver, event)
Other solutions for creating a custom QComboBox that does not rely on setting QStandardItem values work (for example, by creating a custom QStandardItemModel that creates the same functionality).